- Patients with histologically proven intracranial glioblastoma multiforme (GBM) or gliosarcoma (GS). Patients will be eligible if the original histology was low-grade glioma and a subsequent histological diagnosis of a GBM or GS is made. Patients must have evidence of progression of the GBM or GS on MRI or CT scan. Patient must have failed prior chemoradiation with temozolomide and any other therapies except BEV (group A), or must have failed primary chemoradiation and a BEV-incorporating treatment (group B).